JPWO2016002855A1 - Base station apparatus and terminal apparatus - Google Patents

Abstract

In the LTE-A system, there is a problem that stable communication cannot be performed when there is time for another system to occupy the unlicensed band being used. A base station device that communicates with a terminal device in a second frequency band different from the first frequency band that can be used exclusively, a wireless transmission unit that transmits data and control information to the terminal device, and the terminal device A wireless reception unit for receiving transmitted data and control information, wherein the wireless transmission unit transmits data to the terminal device, and another system receives the ACK / NACK reception timing with respect to the data transmission. When performing communication in a frequency band, the radio reception unit performs reception processing of ACK / NACK transmitted from the terminal apparatus in the first uplink subframe after the communication of the other system is completed.

Description

  The present invention relates to a base station apparatus and a terminal apparatus.

  Standardization of the LTE (Long Term Evolution) system (Rel. 8 and Rel. 9), which is the wireless communication system of the 3.9th generation mobile phone, has been completed, and now as one of the 4th generation wireless communication systems, The LTE-A (also referred to as LTE-Advanced, IMT-A, etc.) system (Rel. 10 or later), which is a further development of the LTE system, is being standardized.

  In LTE systems and LTE-A systems, it is necessary to cope with the rapid increase in data traffic. In addition to introducing technologies to improve peak data rates and frequency utilization efficiency, securing frequency resources is also an important issue. is there. Until now, the LTE system and LTE-A system have been premised on the use of a so-called licensed band (licensed band) that has been approved for use by countries and regions where wireless operators provide services. The frequency band is limited.

  Therefore, recently, provision of an LTE system (also referred to as LTE-U) using a frequency band called an unlicensed band that does not require permission from the country or region has been discussed (non-patent literature). 1). In the LTE-A system, CA (Carrier Aggregation) technology is adopted in which one system band of the LTE system is a component carrier (also referred to as CC: Component Carrier or Serving cell) and communication is performed using a plurality of CCs. Yes. This CA technology is also applied to an unlicensed band, and utilization of the unlicensed band is expected as one of the methods that can cope with a rapid increase in data traffic.

  In addition to an unlicensed band, a frequency band called a white band (white space) that is not actually used for the purpose of preventing interference between frequencies (for example, a region allocated for television broadcasting, Frequency bands that are not used by certain operators) or shared frequency bands that have been allocated exclusively to specific operators but are expected to be shared by multiple operators in the future. It may be used in the future.

RP-140259, “Study on Licensed-Assisted Access using LTE,” 3GPP TSG RAN Meeting # 63, March, 2013

  However, in the unlicensed band, as represented by the IEEE 802.11 system, it is also used for communication by RAT (Radio Access Technology) different from LTE. Therefore, it is necessary that the LTE-A system and other systems coexist. is there. In particular, since the conventional LTE-A system is premised on the use of a license band, the design is not designed in consideration that the frequency band to be used may be occupied by another system. Therefore, in the LTE-A system, there is a problem that stable communication cannot be performed when there is time for another system to occupy the unlicensed band being used. Also, when the LTE-A system uses a frequency band other than a license band such as a white band (white space), there is a possibility that other systems may be interfered as in the case of using an unlicensed band. There are similar issues.

  The present invention has been made in view of the above points. When the LTE-A system uses an unlicensed band or white band in common with another system, the LTE-A system uses the unlicensed band. An object is to provide a data transmission method that realizes stable communication even when another system occupies an unlicensed band.

  (1) The present invention has been made to solve the above-described problems, and one aspect of the present invention communicates with a terminal device in a second frequency band different from the first frequency band that can be used exclusively. A wireless transmission unit that transmits data and control information to the terminal device, and a wireless reception unit that receives data and control information transmitted from the terminal device, the wireless transmission Unit transmits data to the terminal device, and when another system is communicating in the second frequency band at the reception timing of ACK / NACK for the data transmission, the wireless reception unit In the first uplink subframe after communication is completed, reception processing of ACK / NACK transmitted from the terminal apparatus is performed.

  (2) In addition, according to an aspect of the present invention, the wireless transmission unit transmits resource allocation control information for data transmission of the terminal device, and the other system is configured to transmit the data allocation timing for the resource allocation. When communication is performed in two frequency bands, the wireless reception unit performs reception processing of data transmitted from the terminal device in the first uplink subframe after the communication of the other system is completed.

  (3) Moreover, one aspect of the present invention is a base station apparatus that communicates with a terminal apparatus in a second frequency band different from the first frequency band that can be used exclusively and the first frequency band, A wireless transmission unit that transmits data and control information to the terminal device and a wireless reception unit that receives data and control information transmitted from the terminal device, wherein the wireless transmission unit transmits data to the terminal device; When another system is communicating in the second frequency band at the reception timing of ACK / NACK for the data transmission, the radio reception unit transmits an ACK transmitted from the terminal apparatus in the first frequency band. / NACK reception processing is performed.

  (4) According to another aspect of the present invention, the wireless reception unit receives data transmitted from the terminal device, and another system transmits the second frequency at an ACK / NACK transmission timing for the data transmission. When communication is performed in a band, ACK / NACK is transmitted to the terminal device in the first frequency band.

  (5) According to another aspect of the present invention, there is provided a data amount management unit that manages a downlink buffered data amount, and when there is no downlink buffered data amount, the wireless transmission unit Notifies NAV by RTS or CTS-to-Self, or transmits dummy data.

  (6) Moreover, one aspect of the present invention is a terminal device that communicates with a base station apparatus in a second frequency band different from the first frequency band that can be used exclusively, and is transmitted from the base station apparatus. An effective subframe determination unit that detects a synchronization signal to be received, a reception signal detection unit that performs reception processing of a data signal transmitted from the base station device, and a wireless transmission unit that transmits a signal to the base station device. When the wireless transmission unit transmits an ACK / NACK indicating whether the data signal transmitted from the base station apparatus has been correctly received by the reception signal detection unit, the wireless transmission unit performs four sub-steps from the reception timing of the data signal. The uplink subframe after the frame and the notification that the other system than the base station apparatus is not communicating in the second frequency band is received by the effective subframe determination unit Transmitting the ACK / NACK after the.

  (7) Moreover, one aspect of the present invention includes a control signal detection unit that detects control information including resource allocation used for data transmission to the base station apparatus, and the control signal detection unit includes the base station When detecting control information including resource allocation used for data transmission transmitted from a device, the radio transmission unit is an uplink subframe four subframes after the timing of receiving the resource allocation, and the base station device Data is transmitted to the base station apparatus after receiving notification that another system is not communicating in the second frequency band.

  (8) According to another aspect of the present invention, there is provided a radio reception unit that performs carrier sense for determining whether another system is performing communication in the second frequency band, and the radio reception unit includes a downlink. The carrier sense is performed in the subframe that switches from uplink to uplink.

  (9) In addition, according to an aspect of the present invention, in a subframe in which the radio reception unit performs carrier sense and switches from a downlink to an uplink, ACK / NACK for data to be transmitted to the base station apparatus or downlink data is transmitted. This is a subframe that switches from the downlink before the subframe to be uplinked to the uplink.

  (10) Further, according to one aspect of the present invention, the radio reception unit performs carrier sense only in a frequency band in which ACK / NACK for data to be transmitted to the base station apparatus or downlink data is transmitted.

  (11) In addition, according to one aspect of the present invention, the effective subframe determination unit cannot detect the synchronization signal transmitted from the base station apparatus, or as a result of carrier sense of the radio reception unit, When another system is communicating in a frequency band, the radio reception unit uses the first frequency band for transmitting ACK / NACK for data to be transmitted to the base station apparatus or downlink data.

  According to the present invention, it is possible to efficiently share information as to whether the base station apparatus and the terminal apparatus can use the unlicensed band or cannot be used because other systems occupy it.

It is a figure which shows an example of a structure of the system which concerns on this invention. It is a figure which shows the frame structure of TDD of a LTE system. It is a figure which shows an example of the frame structure which concerns on this invention. It is a figure which shows an example of a structure of the base station apparatus which concerns on this invention. It is a figure which shows an example of a structure of DL signal generation part 101 which concerns on this invention. It is a figure which shows an example of a structure of the terminal device which concerns on this invention. It is a figure which shows an example of the frame structure which concerns on this invention. It is a figure which shows an example of the multiplexing method of the synchronizing signal which concerns on this invention. It is a figure which shows an example of the multiplexing method of the synchronizing signal which concerns on this invention. It is a figure which shows an example of the downlink ACK / NACK transmission which concerns on this invention. It is a figure which shows an example of the downlink ACK / NACK transmission which concerns on this invention. FIG. 4 is a diagram illustrating an example of uplink ACK / NACK transmission according to the present invention. FIG. 4 is a diagram illustrating an example of uplink ACK / NACK transmission according to the present invention. It is a figure which shows an example of the downlink ACK / NACK transmission which concerns on this invention. It is a figure which shows an example of the downlink ACK / NACK transmission which concerns on this invention.

(First embodiment)
Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows an example of the configuration of a system according to the present invention. The system includes a macro base station apparatus 10, an ULB base station apparatus 11, and terminal apparatuses 21 and 22. Note that the number of terminal devices (terminals, mobile terminals, mobile stations, UE: User Equipment) is not limited to two, and the number of antennas of each device may be one or plural. In addition, the macro base station apparatus 10 performs communication using a so-called licensed band, which is licensed from the country or area where the wireless service provider provides the service, and the ULB base station apparatus 11 receives information from the country or area. Although communication using a so-called unlicensed band that does not require use permission is performed, the present invention is not limited to this example. For example, the macro base station apparatus 10 may support not only a license band but also an unlicensed band communication, and a pico base station apparatus (Pico eNB: evolved Node B, SmallCell, Low Power Node, also called Remote Radio Head) may support unlicensed band communication. Further, the unlicensed band may be only a downlink (downlink or downlink) that is communication from the ULB base station apparatus 11 to the terminal apparatus 21, or not only from the downlink but also from the terminal apparatus 21 to the ULB base station apparatus 11. Uplink (uplink or uplink) that is communication of the above may also be supported. In this specification, an unlicensed band is described as an example of a frequency band other than the license band, but the present invention is not limited to this.

  The terminal device 21 can communicate with at least one of the macro base station device 10 and the ULB base station device 11. On the other hand, the terminal device 22 is connected only to the macro base station device 10. In such a case, the terminal device 21 can communicate with a license band component carrier (also referred to as CC: Component Carrier or Serving cell) and / or an unlicensed band CC. However, if the CC of the unlicensed band (hereinafter referred to as ULB-CC) is occupied by another system (for example, 802.11a, b, g, n, ac, etc.), the terminal device 21 uses the license band. Can be communicated with only CC (hereinafter referred to as LB-CC). When performing communication using ULB-CC, at least one of ULB base station apparatus 11 and terminal apparatus 21 confirms whether ULB-CC is being used by another system, for example, carrier sense (for example, listen before talk Method). For example, the ULB base station apparatus 11 or the terminal apparatus 21 can start communication based on an access method called CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance). As a specific example of the carrier sense, it is determined whether another system is using whether or not the reception level (for example, RSSI: Received Signal Strength Indicator) of the carrier frequency exceeds a threshold value. Note that ULB-CC is described assuming that TDD (also referred to as Time Division Duplex or frame structure type 2) is applied, but also supports FDD (also referred to as Frequency Division Duplex or frame structure type 1). good.

  FIG. 2 shows a TDD frame configuration of the LTE system. From the figure, in the TDD of the LTE system, a plurality of uplink-downlink configurations are prepared, and are appropriately set in units of CCs. D is a downlink subframe, U is an uplink subframe, S is a special subframe, and the special subframe is a GP (Guard Period) and a downlink pilot time slot (DwPTS) necessary for switching from the downlink to the uplink. ), And consists of an uplink pilot time slot (UpPTS). Periods for switching from the downlink to the uplink include 5 msec (configuration # 0, 1, 2, 6) and 10 msec (configuration # 3, 4, 5). The D, U, and S patterns used in this cycle are repeated. Since the LTE system and the LTE-A system can occupy and use the license band, communication is always performed in any pattern.

  FIG. 3 shows an example of a frame configuration according to the present invention. In the unlicensed band ULB-CC, in order to coexist with other systems, carrier sense (CS: Carrier Sense) is required before the start of communication. Therefore, subframe # 0 and subframe # in C in the figure are used. 5 is a period for carrier sense. In subframes # 0 and # 5, at least the ULB base station apparatus 11 performs carrier sense, and when other systems are not using ULB-CC, downlink transmission is started from subframe # 1. When ULB base station apparatus 11 performs carrier sense in subframes # 0 and # 5 and another system uses ULB-CC, it can be confirmed that the other system is not used in the carrier sense subframe. No transmission is performed. Specifically, when it is determined that another system is using ULB-CC as a result of carrier sense of subframe # 0, ULB base station apparatus 11 sets subframes # 1 to # 4 as invalid subframes. I reckon. That is, communication using ULB-CC between the ULB base station apparatus 11 and the terminal apparatus is not performed in subframes # 1 to # 4. On the other hand, as a result of carrier sense of subframe # 0, when it is determined that another system does not use ULB-CC, ULB base station apparatus 11 regards subframes # 1 to # 4 as effective subframes. That is, communication using ULB-CC between the ULB base station apparatus 11 and the terminal apparatus is performed in subframes # 1 to # 4.

  FIG. 4 shows an example of the configuration of the base station apparatus according to the present invention. However, the minimum blocks necessary for the present invention are shown. The figure shows an example of the configuration of the ULB base station apparatus 11, but a base station apparatus (for example, the macro base station apparatus 10) that performs communication only in the LB-CC of the license band has the same configuration except that the CS determination unit 106 is not provided. It is. The ULB base station apparatus 11 receives the control information transmitted by PUCCH (Physical Uplink Control CHannel) or the control information transmitted by PUSCH (Physical Uplink Shared CHannel) from the terminal apparatus by the receiving antenna 104. In the carrier sense subframe, reception processing is performed to confirm whether another system is using the ULB-CC. In the case of an uplink subframe, the radio reception unit 105 down-converts the received signal to a baseband frequency, performs A / D (Analog / Digital) conversion, and removes CP (Cyclic Prefix) from the digital signal. The signal is input to the UL signal demodulator 107. Thereafter, the UL signal demodulator 107 determines channel quality information (CSI: Channel State Information), SR (Scheduling Request), ACK / NACK (Acknowledgement / Negative Acknowledgement), RACH (Random Access CHannel) from the control information after CP removal. A signal or the like is extracted and input to the DL signal generation unit 101. The UL signal demodulator 107 demodulates the data signal and detects an uplink data bit string.

  On the other hand, in the case of a carrier sense subframe, radio reception section 105 inputs a received signal to CS determination section 106. As a result of the carrier sense, the CS determination unit 106 determines whether or not another system is using the ULB-CC, and sets up to the next subframe of the carrier sense as an effective subframe or an invalid subframe. To determine whether to perform communication by ULB-CC. Note that, as a result of carrier sense, even if no ULB-CC is used by another system, an invalid subframe may be used when there is no downlink transmission data. The CS determination unit 106 inputs information on the availability of ULB-CC to the DL signal generation unit 101.

  FIG. 5 shows an example of the configuration of the DL signal generation unit 101 according to the present invention. The DL signal generation unit 101 outputs the ULB-CC availability information input from the CS determination unit 106 to the S / P unit 1011, the synchronization signal generation unit 1016, the control signal generation unit 1017, and the reference signal generation unit 1018. . DL signal generation section 101 outputs uplink control information input from UL signal demodulation section 107 to S / P section 1011 and control signal generation section 1017. The S / P unit 1011, the synchronization signal generation unit 1016, the control signal generation unit 1017, and the reference signal generation unit 1018 do not process anything when ULB-CC cannot be used (when determined as an invalid subframe). When ULB-CC can be used (when determined as a valid subframe), the following processing is performed. The S / P unit 1011 receives ACK / NACK of the previous transmission opportunity from the UL signal demodulator 107, and when an ACK is input, divides a new data bit string into the number of transmission streams. When the NACK is input, the S / P unit 1011 divides the data bit string transmitted at the previous transmission opportunity into the number of transmission streams. In the present embodiment, the case where the number of streams is two will be described. However, the number of streams may be any number or one. The data signal generation units 1012-1 and 1012-2 generate a data transmission signal sequence from the data bit sequence. Here, the processing of the data signal generation units 1012-1 and 1012-2 includes signal generation for each antenna port by error correction coding, puncturing and modulation based on MCS (Modulation and Coding Scheme), and multiplication by a precoding matrix. Allocating signal sequences to resources used for downlink based on resource allocation information. The resource is an RB (Resource Block) composed of 12 subcarriers and 1 subframe, or an RBG (Resource Block Group) obtained by grouping a plurality of RBs. However, the number of subcarriers constituting a resource block is not limited to the above example, and one resource block may be one subcarrier and allocation may be performed in units of subcarriers. Further, the resource allocation information may indicate allocation of the entire subcarriers included in one ULB-CC, and may be information on which ULB-CC is used when there are a plurality of ULB-CCs. good. The resource allocation information may be information indicating allocation subcarriers from all subcarriers of a plurality of ULB-CCs.

  The synchronization signal generation unit 1016 generates a PSS / SSS (Primary Synchronization Signal / Secondary Synchronization Signal) and inputs it to the synchronization signal multiplexing units 1013-1 and 1013-2. The synchronization signal multiplexing sections 1013-1 and 1013-2 multiplex the data transmission signal sequence and the PSS / SSS. The PSS / SSS multiplexing method in this embodiment will be described later. Next, a control signal multiplexing unit generates a signal obtained by multiplexing the PDCCH (Physical Downlink Control CHannel), EPDCCH (Enhanced PDCCH), etc., which are control signals generated by the control signal generation unit 1017, and a synchronization signal and a data transmission signal sequence. Multiplexed by 1014-1 and 1014-2. The downlink reference signal generated by the reference signal generation unit 1018, for example, CRS (Cell-Specific Reference Signal), CSI-RS (Channel State Information Reference Signal), DMRS (De-Modulation Reference Signal), is a reference signal multiplexing unit. 1015-1 and 1015-2, and multiplexed with the outputs of the control signal multiplexing sections 1014-1 and 1014-2, respectively. The IFFT units 1019-1 to 1019-2 convert the signal sequence from the frequency domain signal sequence to the time domain signal sequence by performing IFFT (Inverse Fast Fourier Transform) on the signal sequence.

  Radio transmitting sections 102-1 to 102-2 insert a CP into the time domain signal sequence, convert it into an analog signal by D / A (Digital / Analog) conversion, and transmit the converted signal for transmission Upconvert to the radio frequency to be used. Radio transmitting sections 102-1 to 102-2 amplify the up-converted signal with a PA (Power Amplifier), and transmit the amplified signal via transmitting antennas 103-1 to 103-2. As described above, in the downlink, an OFDM (Orthogonal Frequency Division Multiplexing) signal is transmitted to the terminal device.

  FIG. 6 shows an example of the configuration of the terminal device according to the present invention. Reception is performed by the receiving antennas 201-1 to 201-2. Radio receiving sections 202-1 to 202-2 downconvert the received signal to a baseband frequency, and perform A / D conversion on the downconverted signal to generate a digital signal. Further, radio reception sections 202-1 to 202-2 input a signal obtained by removing CP from the digital signal to effective subframe determination section 210.

  The effective subframe determination unit 210 detects PSS / SSS at a signal reception timing including PSS / SSS described later. When the PSS / SSS detection fails, the ULB base station apparatus 11 determines that the ULB-CC is used by another system or there is no data signal to be transmitted, and the terminal apparatus performs until the next carrier sense subframe. Treat as invalid subframe. The terminal apparatus does not perform downlink data or control signal reception processing in the invalid subframe. For example, when detection of PSS / SSS included in SFN # 0 to # 4 fails in the frame configuration example of FIG. 3, ULB-CC SFN # 0 to # 4 are not used. Here, the failure of PSS / SSS detection is when the received power falls below a preset threshold or when the correlation value falls below the threshold. Next, when the PSS / SSS detection is successful, the terminal apparatus determines that ULB-CC is used, and the terminal apparatus treats it as an effective subframe until the next carrier sense subframe. The terminal apparatus performs downlink reception processing and uplink transmission processing in the effective subframe. For example, when the PSS / SSS included in SFN # 0 to # 4 is successfully detected in the frame configuration example of FIG. 3, ULB-CC SFN # 0 to # 4 are used. If the PSS / SSS is successfully detected at the signal reception timing that does not include PSS / SSS, the valid subframe determination unit 210 inputs the received signal to the FFT units 203-1 to 203-2, and the PSS / SSS is received. If the SSS detection fails, the received signal is discarded.

  The FFT units 203-1 to 203-2 convert the input reception signal sequence from a time domain signal sequence to a frequency domain signal sequence by fast Fourier transform, and the frequency domain signal sequence is converted to control signal separation units 205-1 to 205-. Enter in 2. Control signal demultiplexing sections 205-1 to 205-2 demultiplex signals transmitted on PDCCH and EPDCCH in the downlink subframes of the effective subframes, and input them to control signal detection section 209. The control signal separation units 205-1 to 205-2 also separate the RRC (Radio Resource Control) signal when it is received, and input it to the control signal detection unit 209. The control signal detection unit 209 detects a DCI (Downlink Control Information) format addressed to the own station transmitted by PDCCH or EPDCCH by blind decoding. Further, the control signal detection unit 209 detects an RRC signal. The control signal detection unit 209 inputs the detected control information to the reception signal detection unit 207.

  Reference signal demultiplexing sections 206-1 to 206-2 separate the input signal into a reference signal and a data signal, and input them to propagation path estimation section 208 and received signal detection section 207, respectively. The propagation path estimation unit 208 estimates the frequency response of the demodulation propagation path (channel) using the input reference signals CRS, CSI-RS, and DMRS, and detects the estimated frequency response for demodulation as a received signal. Input to the unit 207. In addition, since the channel estimation unit 208 notifies (reports) the channel quality information (CSI) estimated from CRS or CSI-RS to the base station apparatus periodically or aperiodically, it is not shown in the drawing. The information is input to the control information generation unit 215. The reception signal detection unit 207 detects a downlink data signal. The received signal detection unit 207 uses the equalization processing based on the frequency response of the propagation path, the demodulation processing based on the modulation scheme notified in the DCI format, and the bits obtained by demodulation based on the error correction coding information notified in the DCI format. A sequence LLR (Log Likelihood Ratio) error correction decoding process is performed. Received signal detection section 207 makes a hard decision on the decoded LLR sequence, and outputs a bit sequence if there is no error in cyclic redundancy check (CRC). The reception signal detection unit 207 inputs the presence / absence of an error in the reception data to the UL control information generation unit 215. This information is used for transmission of ACK / NACK.

  On the other hand, the effective subframe determination unit 210 stores the PSS / SSS detection result and the frame configuration used in the ULB-CC notified in advance. It is assumed that the frame configuration is notified by an upper layer control signal, such as RRC signaling. However, it may be notified by a physical layer control signal. A frame configuration example used in ULB-CC is the example described in FIG. In the example shown in the figure, the configurations # 0 to # 3 have a 5-subframe cycle for the carrier sensed subframe, and the configurations # 4 to # 9 have a 10-subframe cycle for the carrier sensed subframe. However, the configuration example of the frame used in the ULB-CC is not limited to that in FIG. 7, and may include a carrier sense subframe and a downlink subframe. For example, the ratio between the downlink and uplink subframes and the period of the subframe for carrier sensing may be configured not shown in FIG.

  When the information of the detection result of the PSS / SSS indicates successful detection, the valid subframe determining unit 210 transmits the notified uplink subframe timing information (uplink valid subframe information) as a UL signal. The data is input to the generation unit 211 and the UL control information generation unit 215. In addition, when the information of the detection result of PSS / SSS indicates successful detection, the valid subframe determination unit 210 uses the notified downlink subframe timing information (information of the downlink valid subframe). This is input to the control signal separators 205-1 and 205-2. The valid subframe determination unit 210 performs no processing when the information of the detection result of PSS / SSS indicates a detection failure (determined as an invalid subframe). The UL signal generation unit 211 converts an uplink data signal into a DFTS-OFDM (also referred to as Discrete Fourier Transform Spread OFDM, SC-FDMA) signal. In this embodiment, DFTS-OFDM is used, but the present invention is not limited to this, and a multicarrier signal such as OFDM or MC-CDMA may be used. The processing applied in the UL signal generation unit 211 includes error correction coding, modulation, DFT, frequency resource allocation, IFFT, and the like. The UL control information generation unit 215 receives ACK / NACK information from the received signal detection unit 207, and further receives CSI information from the propagation path estimation unit 208 (not shown). The UL control information generation unit 215 converts ACK / NACK and periodic CSI into a UCI (Uplink Control Information) format transmitted on the PUCCH, and inputs it to the UL control information multiplexing unit 212. The UL control information multiplexing unit 212 multiplexes uplink data and control information. However, in the case where PUSCH and PUCCH are not transmitted simultaneously, a transmission frame is composed of only one of the signals. UL control information generation section 215 generates and transmits an SR or RACH signal when making an uplink resource allocation request. Here, SR is transmitted by PUCCH, and the RACH signal uses a predetermined resource. The uplink signal is transmitted via the wireless transmission unit 213 and the transmission antenna 214.

  Here, the case where the uplink control signal is transmitted by ULB-CC has been described. However, when the uplink control signal is transmitted only by LB-CC, UL control information is transmitted with respect to the signal transmitted to ULB-CC. The generation unit 215 does nothing. Moreover, although the case where the uplink data signal is transmitted by ULB-CC has been described, a configuration in which no uplink subframe exists in TDD is used (or set), or ULB-CC is FDD. In the case of only the downlink CC (serving cell), the UL signal generation unit 211, the UL control information multiplexing unit 212, the UL control information generation unit 215, the radio transmission unit 213, and the transmission antenna 214 are used only when transmitting to the LB-CC. To do.

  FIG. 3 and FIG. 7 show subframe configurations. Each subframe is composed of a plurality of OFDM symbols, and in the LTE system, 14 OFDM symbols constitute one subframe. Here, although the number of OFDM symbols in one subframe is not limited in the present invention, an example of 14 OFDM symbols (symbols # 0 to # 13) will be described. In the present invention, the number of subframes in one frame is not limited, but an example of 10 subframes (subframes # 0 to # 9) will be described. First, in the LTE system, in the case of TDD, PSS is the third OFDM symbol (symbol # 2) of subframes # 1 and # 6, and SSS is the seventh OFDM symbol (symbol # 6) of subframes # 0 and # 5. In the case of FDD, PSS is the last OFDM symbol (symbol # 13) of subframes # 0 and # 5, and SSS is the sixth OFDM symbol (symbol # 5) of subframes # 0 and # 5. Be placed.

  Here, when applying a frame configuration including a carrier sense subframe before data transmission as shown in FIG. 3 by TDD in ULB-CC, the terminal apparatus identifies a subframe in which data can be transmitted and received at an earlier timing. There is a need. The PSS of the conventional LTE system is arranged in the first subframe of the downlink of FIG. 3, but is not arranged in the first OFDM symbol because of the third OFDM symbol. Also, the SSS of the conventional LTE system is arranged in the seventh OFDM symbol of the carrier sense subframe of FIG. Therefore, effective subframes cannot be efficiently identified between the ULB base station apparatus and the terminal apparatus.

FIG. 8 shows an example of a synchronization signal multiplexing method according to the present invention. In the figure, 7 OFDM symbols are 1 slot and 2 slots are 1 subframe (14 OFDM symbols). FIG. 8 is an example in which PSS / SSS is arranged in the first OFDM symbol of subframe #N _SS in ULB-CC. #N _SS indicates the first downlink subframe after carrier sense. Moreover, PSS and SSS have shown the example arrange | positioned at a different resource block. Therefore, the synchronization signal multiplexing sections 1013-1 and 1013-2 of the ULB base station apparatus set PSS as RB # X _PSS to RB # X _PSS + L _PSS (the number of resource blocks is L _PSS +1), and SSS as RB # X _SSS to RB. #X _SSS + L _SSS (the number of resource blocks is L _SSS +1). Conventionally, PDCCH is arranged in the first OFDM symbol, but PDCCH is not arranged in the resource block in which PSS and SSS are arranged. Further, only the EPDCCH is used in the ULB-CC, and control signals such as PDCCH and EPDCCH may be transmitted only in the LB-CC capable of stable communication without being affected by the communication of other systems. Since the ULB base station apparatus arranges the PSS and SSS as described above in the LB-CC and arranges the PSS and SSS in the ULB-CC as shown in FIG. 8, the frequency band used for communication is LB-CC or ULB- The arrangement of PSS and SSS may be changed depending on the CC. Note that the number of resource blocks in which PSS and SSS are arranged may be all resource blocks (all subcarriers) that can be used for transmission, or signals for all resource blocks may be generated and arranged using a Zadoff-Chu sequence or the like. good. Further, it is not necessary to arrange two Zadoff-Chu sequences in PSS and SSS, and a signal to be arranged in the kth subcarrier may be generated by exp (−jπuk (k + 1) / N). However, N may be generated as a maximum prime number equal to or less than the number of subcarriers in which signals are arranged, and u may be generated as a value determined based on a cell ID or the like. Moreover, PSS and SSS may be arrange | positioned at a discontinuous subcarrier, for example, may be arrange | positioned at equal intervals.

  When the PSS / SSS is transmitted as shown in FIG. 8, the terminal apparatus determines the PSS / SSS included in the first OFDM symbol of the first downlink subframe after the carrier sense subframe by the effective subframe determination unit 210. To detect. Therefore, if PSS / SSS is not detected in the first OFDM symbol, it is determined that control information and a reference signal are not transmitted from the ULB base station apparatus, and RRM (Radio Resource Management) using a blind reference or a downlink reference signal is determined. ) No need to perform measurements. Therefore, when PSS / SSS is not included in the first OFDM symbol of the first downlink subframe after the carrier sense subframe, it is determined whether the OFDM symbol including PSS / SSS is an effective subframe. Because it is not possible, reception processing is required. On the other hand, in this embodiment, when it is not an effective subframe, unnecessary reception processing can be omitted, and the power consumption of the terminal device can be reduced.

  In the present embodiment, one subframe has been described as 1 msec, but the present invention is not limited to this example and may be different. In this embodiment, the carrier sense subframe cycle has been described as an example of a 5 subframe cycle and a 10 subframe cycle. However, the present invention is not limited to this cycle, and the carrier sense subframe cycle is determined within a predetermined cycle. The pattern of downlink and uplink subframes may be repeated. In this embodiment, both the PSS and the SSS are arranged in the first OFDM symbol of the first downlink subframe after the carrier sense subframe, but only one of the PSS and the SSS is placed in the carrier sense subframe. It may be arranged in the first OFDM symbol of the first downlink subframe after the frame. In this embodiment, an example is shown in which PSS and SSS are arranged only in one OFDM symbol in one subframe, but they may be arranged in two or more OFDM symbols in one subframe, for example, symbol # 0 and symbol It may be arranged in # 7 or symbol # 0 and symbol # 13. Further, when PSS and SSS are arranged in a plurality of OFDM symbols, the arranged resource blocks may be changed for each OFDM symbol. In this embodiment, an example in which transmission is started in a downlink subframe after a carrier sense subframe has been described. However, before transmission of the downlink, the ULB base station apparatus performs RTS (Request to Send) or CTS (Clear to Send) -to-self may be transmitted. In this case, a NAV (Network Allocation Vector) may be set in the RTS. The ULB base station apparatus may transmit RTS or CTS-to-self transmission in a part of the carrier sense subframe.

  In the present embodiment, the frame configuration example is shown in FIG. 7 as an example of TDD, but it is not necessary to be a downlink subframe immediately after the carrier sense subframe as in the frame configuration example of FIG. It is also good. For example, the configuration of the subframes may be C, U, U, U, D, C, U, U, D, D, C, U, D, D, D. In this case, the terminal device also needs to sense the carrier in the carrier sense subframe, and when it is determined as a valid subframe as a result of the carrier sense, the terminal device transmits data in the uplink subframe, and the first of the valid subframes. In the downlink subframe, a known signal such as PSS / SSS, a reference signal, and a training symbol may be transmitted as in the present embodiment. In addition, the present embodiment can also be applied to FDD, and when ULB-CC is a downlink CC, it becomes as shown in configuration 2 or configuration 8 which is a frame configuration of only D and C in FIG. In the first downlink subframe of the frame, PSS / SSS transmission similar to that of the present embodiment may be performed. Although the present embodiment has been described by focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, the ULB base station apparatus performs carrier sense in each ULB-CC, determines whether it is a valid subframe or an invalid subframe based on the carrier sense result for each ULB-CC, and the first downlink of the valid subframe. In the subframe, the same PSS / SSS transmission as in the present embodiment may be performed. The timing of the ULB-CC subframe of this embodiment may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus. In the present embodiment, in the ULB-CC, the ULB base station apparatus notifies the effective subframe by transmitting the PSS / SSS in the first OFDM symbol of the first downlink subframe of the effective subframe. It is not limited to this example. For example, instead of PSS / SSS, reference signals such as CRS, CSI-RS, and DMRS may be used, DRS (Discovery Reference Signal), PRS (Positioning Reference Signal), and the like may be used. A known signal such as a symbol may be transmitted.

  As described above, in the present embodiment, the ULB base station apparatus determines whether another system is using ULB-CC in the carrier sense subframe, and if it is usable, the first after the carrier sense subframe is determined. PSS / SSS is transmitted using the first OFDM symbol of the downlink subframe. The terminal device can determine whether or not ULB-CC data can be transmitted and received using the first OFDM symbol of the first downlink subframe, and can share information on the result of efficient carrier sense. As a result, since the terminal device does not need to perform reception processing such as blind decoding when it is not an effective subframe, the amount of calculation can be reduced and power saving can be realized.

(Modification 1 of the first embodiment)
In this modification, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in this modification, only different processing will be described, and description of similar processing will be omitted.

  In this modification, the CS determination unit 106 and the synchronization signal multiplexing units 1013-1 and 1013-2 of the ULB base station apparatus are different from those of the first embodiment. The CS determination unit 106 determines whether another system uses ULB-CC in the carrier sense subframe. In the first embodiment, the CS determination unit 106 performs carrier sense over the entire period of the carrier sense subframe. However, in this modified example, carrier sense is performed with the OFDM symbol excluding the last OFDM symbol (symbol # 13) in the carrier sense subframe. For example, the OFDM symbol for performing carrier sense is the OFDM symbol of the first slot (symbols # 0 to # 6). The synchronization signal multiplexers 1013-1 and 1013-2 determine whether another system is using ULB-CC, and input the result to the synchronization signal generator 1016. The synchronization signal generation unit 1016 generates PSS / SSS as in the first embodiment, and inputs the PSS / SSS to the synchronization signal multiplexing units 1013-1 and 1013-2.

FIG. 9 shows a PSS / SSS multiplexing method according to this modification. This drawing shows an example of placing the PSS / SSS in the last OFDM symbol of the subframe #Nss _2. #Nss ₂ shows the carrier sense of the sub-frame. Moreover, PSS and SSS have shown the example arrange | positioned at a different resource block. Therefore, the synchronization signal multiplexing sections 1013-1 and 1013-2 of the ULB base station apparatus set PSS as RB # X _PSS to RB # X _PSS + L _PSS (the number of resource blocks is L _PSS +1), and SSS as RB # X _SSS to RB. #X _SSS + L _SSS (the number of resource blocks is L _SSS +1). Since the ULB base station apparatus arranges the PSS and SSS in the LB-CC as described above and arranges the PSS and SSS in the ULB-CC as shown in FIG. 9, the frequency band used for communication is LB-CC or ULB- The arrangement of PSS and SSS is changed depending on CC.

  When the PSS / SSS is transmitted as shown in FIG. 9, the terminal apparatus detects the PSS / SSS included in the last OFDM symbol of the carrier sense subframe by the effective subframe determination unit 210. Therefore, if PSS / SSS is not detected in the last OFDM symbol of the carrier sense subframe, it is determined that the subsequent downlink and uplink subframes are not valid subframes, and blind decoding or downlink reference is performed. It is not necessary to perform RRM measurement using signals, downlink data reception, uplink data transmission, and the like.

  In this modification, the example in which PSS / SSS is transmitted using the last OFDM symbol of the carrier sense subframe has been described. However, when applied to the subframe configuration example of FIG. 3, the ULB base station apparatus and terminal are used in ULB-CC. The time for the device to transmit is 4 subframes + 1 OFDM symbol. Therefore, in order to reduce the influence on communication of other systems by ULB-CC, the transmission power used for PSS / SSS transmission may be lowered. In that case, the radio transmission units 102-1 and 102-2 of the ULB base station apparatus include a transmission power control unit. The transmission power control unit lowers the transmission power in the OFDM symbol that transmits PSS / SSS, and downlink data. Alternatively, transmission is performed without reducing transmission power in a subframe or OFDM symbol for transmitting a control signal. Also, the transmission power control unit transmits the LB-CC PSS / SSS without reducing the transmission power even in the OFDM symbol.

  In this modification, an example in which PSS / SSS is transmitted in a carrier sense subframe has been described, but in addition to this, the ULB base station apparatus transmits PSS / SSS even in some OFDM symbols of a downlink subframe. Also good. In this case, the resource block for transmitting the PSS / SSS of the carrier sense subframe and the downlink subframe may be different. For example, the ULB base station apparatus may arrange either PSS or SSS in all resource blocks in a carrier sense subframe, and may arrange PSS and SSS in some resource blocks in a downlink subframe.

  In this modification, the carrier sense subframe cycle has been described as an example of a 5 subframe cycle and a 10 subframe cycle. However, the present invention is not limited to this cycle, and the carrier sense subframe cycle is reduced within a predetermined cycle. The pattern of link and uplink subframes may be repeated. In this modification, both PSS and SSS are arranged in the last OFDM symbol of the carrier sense subframe, but only one of PSS and SSS is arranged in the last OFDM symbol of the carrier sense subframe. You may do it. In this case, a synchronization signal that is not arranged in the last OFDM symbol may be arranged in the last preceding OFDM symbol (symbol # 12) of the carrier sense subframe. In this modification, PSS / SSS is transmitted using the last OFDM symbol of the carrier sense subframe. However, even if the ULB base station apparatus transmits RTS or CTS-to-self before transmission of PSS / SSS. good. In this case, NAV may be set in RTS. The ULB base station apparatus may transmit RTS or CTS-to-self transmission in a part of the carrier sense subframe.

  In this modification, an example of the frame configuration is shown in FIG. 7 as an example of TDD, but it is not necessary to be a downlink subframe immediately after the carrier sense subframe as in the frame configuration example of FIG. It is also good. For example, the configuration of the subframes may be C, U, U, U, D, C, U, U, D, D, C, U, D, D, D. Further, the present modification can also be applied to FDD, and when ULB-CC is a downlink CC, it becomes as in configuration 2 or configuration 8 which is a frame configuration of only D and C in FIG. In the first downlink subframe of the frame, the same PSS / SSS transmission as in the present modification may be performed. Although this modification has been described focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, the ULB base station apparatus performs carrier sense in each ULB-CC, determines whether it is a valid subframe or an invalid subframe based on the carrier sense result for each ULB-CC, and the first downlink of the valid subframe. In the subframe, the same PSS / SSS transmission as in the present modification may be performed. The timing of the ULB-CC subframe in this modification may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus. In this modification, an example is shown in which PSS / SSS is transmitted using the last OFDM symbol of a carrier sense subframe. However, the present embodiment is not limited to this example, and PSS is performed at any timing of a carrier sense subframe. If / SSS is transmitted, it is included in the present invention. In this modification, the ULB base station apparatus notifies the effective subframe by transmitting the PSS / SSS in the last OFDM symbol of the carrier sense subframe in the ULB-CC, but is not limited to this example. . For example, a reference signal such as CRS, CSI-RS, or DMRS may be used instead of PSS / SSS, DRS or PRS may be used, or a known signal such as a training symbol may be transmitted. good.

  As described above, in this modification, the ULB base station apparatus determines whether another system is using ULB-CC in the carrier sense subframe, and if it is usable, the last OFDM in the carrier sense subframe is determined. Transmit PSS / SSS with symbols. The terminal device can determine whether or not ULB-CC data can be transmitted and received by the last OFDM symbol of the carrier sense subframe, and can share information on the result of efficient carrier sense. As a result, the terminal apparatus determines whether the ULB-CC can be used before the downlink subframe, and if it is not an effective subframe, it does not need to perform reception processing such as blind decoding, thereby reducing the amount of calculation. And power saving can be realized.

(Modification 2 of the first embodiment)
In this modification, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in this modification, only different processing will be described, and description of similar processing will be omitted.

  In this modification, PSS / SSS is transmitted in the same manner as in Modification 1 of the first embodiment, and is arranged in the last OFDM symbol of the carrier sense subframe. However, the UL signal generation unit 211 of the terminal device is different from Modification 1 of the embodiment. The UL signal generation unit 211 generates an uplink transmission signal based on uplink subframe timing information notified from the valid subframe determination unit 210. Uplink transmission timing includes an uplink pilot time slot (UpPTS) included in a special subframe in addition to an uplink subframe. In particular, UpPTS is used for SRS and RACH transmission.

Here, the special subframe includes a GP, a downlink pilot time slot (DwPTS), and an uplink pilot time slot (UpPTS). The percentage of GP time included in the special subframe can be changed according to the special subframe configuration. In the case of normal CP in the downlink and uplink, DwPTS is _{T DL = 6592T s, 19760T s} , 21952T s, 24144T s, 26336T s, one of the 13168T _s is specified, UpPTS is _T UL ₌ 2192T _s, 4384T s Is specified. However, _{T s} is the time to meet the 1msec = 30720T _{s. Since T DL} and UpPTS of _{T UL} of DwPTS is uniquely determined in accordance with the special subframe configuration, the time of GP is determined by the _{T GP = 30720T s -T DL -T} UL.

Therefore, the terminal device when transmitting and SRS in UpPTS, starts transmission after _T DL _{+ T GP} of special subframe. Here, in this modification, when the ULB base station apparatus determines that the other system is not using ULB-CC as a result of carrier sense, it occupies time for one OFDM symbol + 4 subframes for transmitting PSS / SSS. To do. If the ULB-CC is occupied by communication between the ULB base station device and the terminal device, other systems cannot be used, so it is preferable to shorten the occupation time. Therefore, in the present modification, the GP time is calculated as T _GP2 = 30720T _s -T _DL -T _UL -T _symb , and the occupied time without reducing the amount of resources that can be used for communication between the ULB base station apparatus and the terminal apparatus. Is reduced to the conventional time of 4 subframes (4 msec). Where T _symb is the time of one OFDM symbol. The UL signal generation unit 211 generates a signal to be transmitted after T _DL + T _GP2 when transmitting SRS or the like using UpPTS. Also, the radio reception unit 105 and the UL signal demodulation unit 107 of the ULB base station apparatus perform reception processing on the assumption that the terminal apparatus has transmitted an uplink signal after T _DL + T _GP2 of the special subframe.

In this modification, when the terminal device calculates the transmission timing of the UpPTS, it has been described that the time GP and _{T GP2} in ULB-CC, the terminal device calculates the transmission timing of the UpPTS in LB-CC In this case, T _GP may be used as usual. Therefore, the terminal apparatus may switch the UpPTS transmission timing of the special subframe between ULB-CC and LB-CC. Further, in this modification, although the terminal device has been described an example of subtracting the time 1OFDM symbol when calculating the T _GP2, may subtract longer than 1OFDM symbols. For example, a compute transmission timings of the UpPTS terminal apparatus by subtracting the time 2OFDM symbols when calculating the _{T GP2.} In such a case, the ULB base station apparatus may use one of the timings, such as after DwPTS, as the OFDM symbol for transmitting PSS / SSS, as the GP is shortened.

  As described above, in the present modification, when the terminal apparatus calculates the UpPTS transmission start timing of the special subframe, a value obtained by subtracting one OFDM symbol from the conventional GP time is applied. Therefore, without reducing the amount of resources that can be used for communication between the ULB base station apparatus and the terminal apparatus, the occupied time is transmitted from the PSS / SSS transmitted in the last OFDM symbol of the carrier sense subframe to the downlink subframe and uplink. The total time of subframes and special subframes can be reduced to the conventional time of 4 subframes (4 msec). Through communication between the ULB base station apparatus and the terminal apparatus, it is possible to reduce a time during which another system cannot communicate with the ULB-CC, and to efficiently use the ULB-CC.

(Second Embodiment)
In the second embodiment of the present invention, as in the previous embodiment, the ULB base station apparatus determines whether the ULB base station apparatus is a valid subframe or an invalid subframe in a carrier sense subframe. A transmission method of ACK / NACK for downlink transmission when transmitting PSS / SSS will be described.

  In the present embodiment, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in the present embodiment, only different processing will be described, and description of similar processing will be omitted.

  When the ULB base station apparatus transmits downlink data, the control signal generator 1017 generates downlink resource allocation information (DL grant) and transmits it to the terminal apparatus. The terminal apparatus detects resource allocation information (DL grant) by blind decoding at control signal detection section 209, and performs data reception processing based on the resource allocation information. As a result of the data reception process, ACK / NACK, which is information indicating whether or not the data is correctly detected, is generated by the UL control information generation unit 215.

  FIG. 10 shows an example of ACK / NACK transmission for the downlink according to the present invention. This figure is an example of timing correspondence when the radio transmission unit 213 of the terminal apparatus transmits uplink control information including ACK / NACK with respect to downlink resource allocation and data reception timing. For example, when the terminal apparatus allocates downlink resource and the data reception timing is any of subframes # 1, # 2, and # 3 of frame # 0, the terminal apparatus allocates downlink resource allocation and data received subframe. ACK / NACK is transmitted in the uplink subframe that comes first after 4 subframes after the frame. In the example of FIG. 10, it is subframe # 9 of frame # 0. Here, for each subframe of carrier sense, it is determined whether the ULB base station apparatus is an effective subframe not occupied by another system or an invalid subframe occupied by another system. First, when subframes # 5 to # 9 of frame # 0 are effective subframes, the terminal device can use subframe # 9 of frame # 0, so subframes # 1, # 2, ACK / NACK for data received in at least one of # 3 is transmitted in subframe # 9 of frame # 0.

  Next, the case where subframes # 5 to # 9 of frame # 0 are invalid subframes will be described with reference to FIG. In the figure, another system is using the carrier sense of subframe # 5 of frame # 0, and the ULB base station apparatus does not transmit PSS / SSS. Since the terminal apparatus cannot detect PSS / SSS, it determines that subframes # 5 to # 9 of frame # 0 are invalid subframes, and does not transmit ACK / NACK in subframe # 9 of frame # 0. Here, if the terminal apparatus transmits ACK / NACK in subframe # 9 of frame # 0, it collides with communication of another system, and the ULB base station apparatus correctly receives ACK / NACK from ULB-CC. Probability of receiving decreases. Therefore, it becomes impossible to realize stable communication with ULB-CC.

  When the ULB base station apparatus determines that subframes # 0 to # 4 of frame # 1 are valid subframes as a result of carrier sense in subframe # 0 of frame # 1, the ULB base station apparatus performs PSS / SSS. Send. By detecting PSS / SSS, the terminal device determines that subframe # 4 of frame # 1 is an uplink subframe that comes first four subframes after the subframe in which downlink data is received, and transmits ACK / NACK. To do.

  In the present embodiment, an example has been described in which information on whether a valid subframe or an invalid subframe is performed between the ULB base station apparatus and the terminal apparatus by detecting PSS / SSS as in the previous embodiment. However, the present invention is not limited to this method. Therefore, the terminal apparatus determines whether it is a valid subframe or an invalid subframe by another method, and the first valid four frames after the subframe from which downlink data is received, excluding the uplink subframe of the invalid subframe. If ACK / NACK is transmitted in the uplink subframe, it is included in the present invention. In addition, this embodiment can also be applied to FDD, and when downlink and uplink CCs exist in the ULB-CC, from the subframe that received the downlink data excluding the uplink subframe of the invalid subframe. ACK / NACK may be transmitted in the uplink ULB-CC effective subframe that comes first after four subframes. Although the present embodiment has been described by focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, the ACK / NACK transmission timing of this embodiment may be applied to each ULB-CC. The timing of the ULB-CC subframe of this embodiment may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus.

  As described above, in the present embodiment, the ULB base station apparatus and the terminal apparatus share information on valid subframes or invalid subframes, and the terminal apparatus transmits downlink data excluding uplink subframes of invalid subframes. ACK / NACK is transmitted in the uplink subframe that comes first four subframes after the received subframe. As a result, even if another system occupies the ULB-CC between the reception of the downlink data and the ACK / NACK transmission, the collision can be avoided, and the deterioration of the communication quality in the ULB-CC can be suppressed. Frequency utilization efficiency is improved.

(Modification 1 of 2nd Embodiment)
In this modification, the ULB base station apparatus determines whether it is a valid subframe or an invalid subframe in the carrier sense subframe as in the second embodiment, and in the case of the valid subframe, the ULB base station apparatus performs PSS / SSS. ACK / NACK transmission method for downlink transmission when transmitting

  In this modification, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in this modification, only different processing will be described, and description of similar processing will be omitted.

  When the ULB base station apparatus performs uplink scheduling, uplink resource allocation information (UL grant) is generated by the control signal generation unit 1017 and transmitted to the terminal apparatus. The terminal apparatus detects resource allocation information (UL grant) by blind decoding in the control signal detection unit 209, and performs data transmission processing based on the resource allocation information. The control signal generation unit 1017 generates ACK / NACK, which is information indicating whether the ULB base station apparatus has been correctly detected as a result of the data reception process. Here, ACK / NACK for uplink data is notified by either or both of PDCCH / EPDCCH and PHICH (Physical Hybrid-ARQ Indicator CHannel).

  FIG. 12 shows an example of ACK / NACK transmission for the uplink according to the present invention. In the figure, the radio transmission unit 213 of the terminal device is the uplink data transmission timing for the uplink resource allocation information, and the radio transmission units 102-1 and 102-2 of the ULB base station device are for the uplink data reception timing. It is an example of the matching of the timing which transmits the control information of downlink containing ACK / NACK. For example, if the reception timing of the uplink resource allocation is any one of subframes # 1, # 2, and # 3 of frame # 0, the terminal device first starts after 4 subframes from the uplink resource allocation. Data is transmitted in the coming uplink subframe. In the example of FIG. 12, it is subframe # 9 of frame # 0. Here, for each subframe of carrier sense, it is determined whether the ULB base station apparatus is an effective subframe not occupied by another system or an invalid subframe occupied by another system. First, when subframes # 5 to # 9 of frame # 0 are effective subframes, the terminal device can use subframe # 9 of frame # 0, so subframes # 1, # 2, Data transmission for uplink resource allocation received in at least one of # 3 is performed in subframe # 9 of frame # 0. However, when subframes # 5 to # 9 of frame # 0 are invalid subframes, except for the uplink subframes of invalid subframes, the first after four subframes from the subframe that received the uplink resource allocation Data is transmitted in the coming uplink subframe.

  When the terminal apparatus performs uplink data transmission in subframe # 9 of frame # 0, the ULB base station apparatus uses a downlink subframe that comes first four subframes after the subframe of uplink data transmission. ACK / NACK for uplink data is transmitted. In FIG. 12, subframes # 0 to # 4 of frame # 1 are effective subframes. At this time, the ULB base station apparatus performs ACK / NACK for uplink data in subframe # 3 of frame # 1. Send.

  Next, the case where subframes # 0 to # 4 of frame # 1 are invalid subframes will be described with reference to FIG. In the figure, another system is using the carrier sense of subframe # 0 of frame # 1, and the ULB base station apparatus does not transmit PSS / SSS. Since the terminal device cannot detect PSS / SSS, it determines that subframes # 0 to # 4 of frame # 1 are invalid subframes, and ACKs for uplink data in subframe # 6 of next frame # 1 at the earliest. It is determined that / NACK is transmitted. Here, if the ULB base station apparatus transmits ACK / NACK in subframe # 3 of frame # 1, it collides with communication of other systems, and the terminal apparatus correctly performs ACK / NACK in ULB-CC. Probability of receiving decreases. Therefore, it becomes impossible to realize stable communication with ULB-CC.

  When the ULB base station apparatus determines that subframes # 5 to # 9 of frame # 1 are valid subframes as a result of carrier sense in subframe # 5 of frame # 1, the ULB base station apparatus performs PSS / SSS. Send. Furthermore, the ULB base station apparatus transmits ACK / NACK for uplink data received in subframe # 9 of frame # 0 in subframe # 6 of frame # 1. This is because subframe # 6 of frame # 1 corresponds to the downlink subframe that comes first four subframes after the subframe in which uplink data is received. By detecting PSS / SSS, the terminal apparatus determines that subframe # 6 of frame # 1 is the first downlink subframe that is four subframes after the subframe in which uplink data was transmitted, and receives ACK / NACK. Process.

  In the present modification, an example has been described in which information on whether a valid subframe or invalid subframe is performed between the ULB base station apparatus and the terminal apparatus by detecting PSS / SSS as in the previous embodiment, but the present invention is not limited to this method. Therefore, the terminal apparatus determines whether the subframe is a valid subframe or an invalid subframe by another method, and excluding the downlink subframe of the invalid subframe, the first valid four frames after the subframe receiving the uplink data. If ACK / NACK is transmitted in the downlink subframe, it is included in the present invention. In addition, this modification can also be applied to FDD, and when there are downlink and uplink CCs in the ULB-CC, from the subframe that received the uplink data except the downlink subframe of the invalid subframe. ACK / NACK may be transmitted in the downlink ULB-CC effective subframe that comes first after four subframes. Although this modification has been described focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, you may apply the ACK / NACK transmission timing of this modification in each ULB-CC. The timing of the ULB-CC subframe in this modification may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus. If there is no valid subframe in a certain period from the uplink resource allocation information or uplink data transmission timing, ACK / NACK for uplink data is transmitted with a different CC (for example, LB-CC). Also good.

  As described above, in the present modification, the ULB base station apparatus and the terminal apparatus share information on valid subframes or invalid subframes, and the terminal apparatus removes uplink data except downlink subframes of invalid subframes. ACK / NACK is transmitted in a downlink subframe that comes first four subframes after the received subframe. As a result, even if another system occupies the ULB-CC between the reception of the uplink data and the ACK / NACK transmission, it is possible to avoid the collision and to suppress the deterioration of the communication quality in the ULB-CC. Frequency utilization efficiency is improved.

(Modification 2 of the second embodiment)
In this modification, as in the second embodiment and the first modification of the second embodiment, it is determined whether the ULB base station apparatus is a valid subframe or an invalid subframe in the carrier sense subframe, and the valid subframe is determined. In this case, a transmission method of ACK / NACK for downlink transmission when the ULB base station apparatus transmits PSS / SSS will be described.

  In this modification, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in this modification, only different processing will be described, and description of similar processing will be omitted.

  When the ULB base station apparatus transmits downlink data, the control signal generator 1017 generates downlink resource allocation information (DL grant) and transmits it to the terminal apparatus. The terminal apparatus detects resource allocation information (DL grant) by blind decoding at control signal detection section 209, and performs data reception processing based on the resource allocation information. As a result of the data reception process, ACK / NACK, which is information indicating whether or not the data is correctly detected, is generated by the UL control information generation unit 215.

  FIG. 14 shows an example of ACK / NACK transmission for the downlink according to the present invention. This figure is an example of timing correspondence when the radio transmission unit 213 of the terminal apparatus transmits uplink control information including ACK / NACK with respect to downlink resource allocation and data reception timing. For example, when the terminal apparatus allocates downlink resource and the data reception timing is any of subframes # 1, # 2, and # 3 of frame # 0, the terminal apparatus allocates downlink resource allocation and data received subframe. ACK / NACK is transmitted in the uplink subframe that comes first after 4 subframes after the frame. In the example of FIG. 14, it is subframe # 9 of frame # 0. Here, for each subframe of carrier sense, it is determined whether the ULB base station apparatus is an effective subframe not occupied by another system or an invalid subframe occupied by another system. First, when subframes # 5 to # 9 of frame # 0 are effective subframes, the terminal device can use subframe # 9 of frame # 0, so subframes # 1, # 2, ACK / NACK for data received in at least one of # 3 is transmitted in subframe # 9 of frame # 0.

  Next, when the ULB base station apparatus performs carrier sense and subframes # 5 to # 7 of frame # 0 are invalid subframes, the operation shown in FIG. 14 is performed. The ULB base station apparatus does not transmit PSS / SSS. Therefore, since the terminal device cannot detect PSS / SSS, it determines that subframes # 5 to # 7 of frame # 0 are invalid subframes. The ULB base station apparatus performs carrier sense in the subframe before the uplink subframe (subframe # 8 of frame # 0). For example, carrier sense is performed in the first slot of subframe # 8 of frame # 0. When the ULB base station apparatus determines that subframes # 8 to # 9 of frame # 0 are valid subframes as a result of carrier sense, the PSS is used in the last OFDM symbol of subframe # 8 of frame # 0 as shown in FIG. / SSS is transmitted. The terminal apparatus detects PSS / SSS in subframe # 8 of frame # 0, determines that subframe # 9 of frame # 0 is a valid subframe, and transmits ACK / NACK.

  In the present modification, an example has been described in which information on whether a valid subframe or invalid subframe is performed between the ULB base station apparatus and the terminal apparatus by detecting PSS / SSS as in the previous embodiment, but the present invention is not limited to this method. In other words, the terminal apparatus determines whether it is a valid subframe or an invalid subframe by another method, and the uplink that comes first after 4 subframes after receiving the downlink data, excluding the uplink subframe of the invalid subframe. If ACK / NACK is transmitted in the link subframe, it is included in the present invention. In addition, although this modification has been described as the timing of ACK / NACK transmission for downlink resource allocation and data reception, this modification may be applied to the timing of uplink data transmission for uplink resource allocation. . In the present modification, an example is shown in which the ULB base station apparatus performs carrier sense in subframe # 8 of frame # 0, but the terminal apparatus performs carrier sense in subframe # 8 and is not occupied by another system. When the frame is determined, ACK / NACK may be transmitted in subframe # 9 of frame # 0. In this modification, when the subframe # 5 of frame # 0 is occupied by another system, the special subframe of subframe # 8 of frame # 0 is described as the carrier sense subframe. It may always be handled as a carrier sense subframe. In addition, this modification can also be applied to FDD, and when downlink and uplink CCs exist in the ULB-CC, from the subframe that received the downlink data excluding the uplink subframe of the invalid subframe. The terminal apparatus may perform carrier sense before the uplink ULB-CC subframe after 4 subframes. Although this modification has been described focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, the transmission timing of ACK / NACK may be determined in each ULB-CC based on the carrier sense result of the terminal device as in this modification. The timing of the ULB-CC subframe in this modification may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus. In addition, when the terminal device performs carrier sense, carrier sense is performed only on the frequency band used for transmission among all frequency bands that can be used for ULB-CC data transmission, and the ULB base station device performs ULB-CC data transmission. All frequency bands that can be used for transmission may be carrier sensed.

  As described above, in the present modification, the ULB base station apparatus and the terminal apparatus share information on valid subframes or invalid subframes, and the terminal apparatus transmits downlink data excluding uplink subframes of invalid subframes. ACK / NACK is transmitted in the uplink subframe that comes first four subframes after the received subframe. As a result, even if another system occupies the ULB-CC between the reception of the downlink data and the ACK / NACK transmission, the collision can be avoided, and the deterioration of the communication quality in the ULB-CC can be suppressed. Frequency utilization efficiency is improved. Furthermore, even if another system occupies the carrier sense subframe before the downlink subframe, the carrier sense is performed before the uplink subframe. As a result, if another system is completed before the uplink subframe, the uplink transmission opportunity increases because only the uplink subframe can be used even if the downlink subframe cannot be used. Frequency utilization efficiency is improved.

(Third embodiment)
In the third embodiment of the present invention, as in the previous embodiment, the ULB base station apparatus determines whether the ULB base station apparatus is a valid subframe or an invalid subframe in the carrier sense subframe. A transmission method of ACK / NACK for downlink transmission when transmitting PSS / SSS will be described.

  In the present embodiment, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in the present embodiment, only different processing will be described, and description of similar processing will be omitted.

  When the ULB base station apparatus transmits downlink data, the control signal generator 1017 generates downlink resource allocation information (DL grant) and transmits it to the terminal apparatus. The terminal apparatus detects resource allocation information (DL grant) by blind decoding at control signal detection section 209, and performs data reception processing based on the resource allocation information. As a result of the data reception process, ACK / NACK, which is information indicating whether or not the data is correctly detected, is generated by the UL control information generation unit 215.

  FIG. 15 shows an example of ACK / NACK transmission for the downlink according to the present invention. This figure is an example of timing correspondence when the radio transmission unit 213 of the terminal apparatus transmits uplink control information including ACK / NACK with respect to downlink resource allocation and data reception timing. For example, if the terminal device is downlink resource allocation and the data reception timing is any one of ULB-CC subframes # 1, # 2, and # 3, the terminal device allocates downlink resource allocation and data received subframes. ACK / NACK is transmitted in the uplink subframe that comes first after 4 subframes after the frame. In the example of FIG. 15, it is ULB-CC subframe # 9. Here, for each carrier sense subframe, whether the ULB base station apparatus is a subframe not occupied by another system (valid subframe) or a subframe occupied by another system (invalid subframe). to decide. First, when the ULB-CC subframes # 5 to # 9 are valid subframes, since the terminal device can use the ULB-CC subframe # 9, the ULB-CC subframes # 1, # 2, ACK / NACK for data received in at least one of # 3 is transmitted in ULB-CC subframe # 9.

  Next, when the ULB base station apparatus performs carrier sense and ULB-CC subframes # 5 to # 7 are invalid subframes, the operation of FIG. 15 is performed. In the figure, another system is used in carrier sense of ULB-CC subframe # 5, and the ULB base station apparatus does not transmit PSS / SSS. Therefore, since the terminal apparatus cannot detect PSS / SSS, it determines that subframes # 5 to # 9 of ULB-CC are invalid subframes, and subframe # of LB-CC instead of subframe # 9 of ULB-CC. 9 sends ACK / NACK. This is because it is important that ACK / NACK is transmitted without error, and when it cannot be transmitted by ULB-CC, it is necessary to transmit it reliably by LB-CC. In addition, when ACK / NACK transmission is possible in both LB-CC and ULB-CC, LB-CC resources may be used preferentially.

  In the present embodiment, an example has been described in which information on whether a valid subframe or an invalid subframe is performed between the ULB base station apparatus and the terminal apparatus by detecting PSS / SSS as in the previous embodiment. However, the present invention is not limited to this method. In other words, the terminal apparatus determines whether it is a valid subframe or an invalid subframe by another method, and the uplink that comes first after 4 subframes after receiving the downlink data, excluding the uplink subframe of the invalid subframe. If ACK / NACK is transmitted in the link subframe, it is included in the present invention. Further, although the present embodiment has been described as the timing of ACK / NACK transmission for downlink resource allocation and data reception, the present embodiment may be applied to the timing of uplink data transmission for uplink resource allocation. . In the present embodiment, an example in which the ULB base station apparatus performs carrier sense in the ULB-CC subframe # 0 is shown. However, in the ULB-CC subframe # 8, the ULB is detected in the ULB-CC subframe # 8 as in Modification 2 of the second embodiment. The base station device or the terminal device may perform carrier sense. In this case, when the terminal apparatus determines that the subframe # 9 is an effective subframe that is not occupied by another system, the ULB-CC subframe # 9 may transmit ACK / NACK in the effective subframe. In this embodiment, when the ULB-CC subframe # 5 is occupied by another system, the special subframe of the ULB-CC subframe # 8 is used as a carrier sense subframe, and the special subframe is always a carrier. It may be treated as a sense subframe. In the present embodiment, an example is shown in which both downlink resource allocation and downlink data transmission are transmitted by ULB-CC. However, downlink resource allocation is LB-CC, and downlink data transmission is ULB-CC. It may be sent by.

  In the present embodiment, an example in which there is one LB-CC is shown. However, a plurality of LB-CCs may exist, and when ACK / NACK cannot be transmitted by ULB-CC, a predetermined LB-CC is used. The LB-CC for transmitting ACK / NACK may be determined based on the priorities of the LB-CC and information such as the LB-CC associated with the ULB-CC. In addition, the present embodiment can also be applied to FDD. When downlink and uplink CCs exist in the ULB-CC, if the uplink ULB-CC is an invalid subframe, the present embodiment is similar to the present embodiment. ACK / NACK may be transmitted by uplink LB-CC.

  As described above, in the present embodiment, the ULB base station apparatus and the terminal apparatus share information on valid subframes or invalid subframes, and the terminal apparatus determines that ULB-CC is an invalid subframe at the transmission timing of ACK / NACK. If it is determined, ACK / NACK is transmitted by LB-CC. As a result, even if another system occupies the ULB-CC between the reception of the downlink data and the ACK / NACK transmission, the collision can be avoided, and the deterioration of the communication quality in the ULB-CC can be suppressed. Frequency utilization efficiency is improved. In this embodiment, the terminal device transmits without delay with respect to the conventional ACK / NACK timing by switching ACK / NACK to LB-CC even if ULB-CC is an invalid subframe at the transmission timing of ACK / NACK. can do. Furthermore, even if another system occupies the carrier sense subframe before the downlink subframe, the carrier sense is performed before the uplink subframe. As a result, if another system is completed before the uplink subframe, the uplink transmission opportunity increases because only the uplink subframe can be used even if the downlink subframe cannot be used. Frequency utilization efficiency is improved.

(Fourth embodiment)
In the fourth embodiment of the present invention, as in the previous embodiment, the ULB base station apparatus determines whether the ULB base station apparatus is a valid subframe or an invalid subframe in the carrier sense subframe. A method for transmitting uplink data when transmitting PSS / SSS will be described.

  In the present embodiment, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in the present embodiment, only different processing will be described, and description of similar processing will be omitted.

  This embodiment will be described with reference to FIG. In the present embodiment, a synchronization signal generation unit 1016 of the ULB base station apparatus is different from that in the first embodiment. When the CS determination unit 106 determines that the subframe # 0 of the frame # 0 is an effective subframe that is not occupied by another system, information on the effective subframe is input to the synchronization signal generation unit 1016. Although not shown, the synchronization signal generation unit 1016 is notified of the amount of data buffered for transmission from the data amount management unit included in the S / P unit 1011. The synchronization signal generation unit 1016 generates the PSS / SSS of the synchronization signal in the case of an effective subframe, but changes the sequence to be generated according to the buffered data amount. For example, when generating a Zadoff-Chu sequence or Gold sequence, the root sequence index and the initial value of the shift register are changed according to the amount of buffered data. In addition, the threshold value of the buffered data amount for determining whether to change the root sequence index or the initial value of the shift register may be determined in advance by the system. For example, a different series of PSS / SSS is generated only when there is no downlink transmission data. Further, although an example of changing the root sequence index and initial value of the sequence has been described, the sequence itself may be changed.

  The terminal device is notified in advance as control information of the sequence used as the PSS / SSS, calculates the correlation value between the candidate sequence to be transmitted and the received PSS / SSS, and the PSS / SSS is transmitted in any sequence. It is determined whether it is done. Here, when the terminal apparatus detects a PSS / SSS sequence used when the amount of data buffered for downlink in the ULB base station apparatus exceeds the threshold, the terminal apparatus is the same as in the previous embodiment. Perform processing. On the other hand, when the amount of data buffered for downlink in the ULB base station apparatus falls below the threshold value, the terminal apparatus performs the following process.

  The terminal apparatus receives uplink resource allocation in any of subframes # 1, # 2, and # 3 of frame # 0 in FIG. 12, and further receives frame # 0 in PSS / SSS transmitted from the ULB base station apparatus. It is determined whether the subframes # 5 to # 9 are effective subframes. When PSS / SSS indicating that subframes # 5 to 9 of frame # 0 are valid subframes is a sequence used when the amount of data buffered for downlink in the ULB base station apparatus exceeds a threshold The terminal apparatus regards subframe # 8 of frame # 0 as a carrier sense subframe. If there is no downlink data, it may be determined that the ULB-CC is not used because another system performs carrier sense in subframes # 6 and 7 of frame # 0. The system may start communication. Therefore, if the terminal device does not perform carrier sense in subframe # 8 of frame # 0 that is before the uplink subframe, there is a possibility of collision with communication of other systems. Therefore, in the present embodiment, it is possible to notify the terminal device whether carrier sense is required before the uplink subframe in the PSS / SSS sequence transmitted from the ULB base station device. Whether or not radio receiving sections 202-1 and 202-2 of the terminal apparatus perform carrier sense in subframe # 8 of frame # 0, and whether or not to transmit uplink data in subframe # 9 of frame # 0 based on the result To decide. If uplink data cannot be transmitted in subframe # 9 of frame # 0, the terminal device transmits uplink data by any of the methods described in the previous embodiment. It is assumed that the terminal device is notified in advance of sequences that the ULB base station device may transmit, or is set in units of system and ULB-CC, and is buffered for these sequences and downlink. It is assumed that the relationship between the data amounts is also notified in the same manner, or is set in units of systems and ULB-CCs.

  This embodiment can also be applied when transmitting downlink ACK / NACK. For example, in the case of FIG. 10, the terminal apparatus receives downlink resource allocation and data in any of subframes # 1 to # 3 of frame # 0, and receives frame # in PSS / SSS transmitted from the ULB base station apparatus. It is determined whether 0 subframes # 5 to # 9 are effective subframes. When PSS / SSS indicating that subframes # 5 to 9 of frame # 0 are valid subframes is a sequence used when the amount of data buffered for downlink in the ULB base station apparatus exceeds a threshold The terminal apparatus regards subframe # 8 of frame # 0 as a carrier sense subframe. Whether or not radio receiving sections 202-1 and 202-2 of the terminal apparatus perform carrier sense in subframe # 8 of frame # 0, and transmits ACK / NACK in subframe # 9 of frame # 0 based on the result To decide. If uplink data cannot be transmitted in subframe # 9 of frame # 0, the terminal apparatus transmits ACK / NACK by any of the methods described in the previous embodiment.

  Also, in the present embodiment, an example has been described in which the terminal apparatus notifies whether or not to perform carrier sense before transmitting ACK / NACK for uplink data or downlink data in a PSS / SSS sequence. Further information may be notified in the / SSS series. For example, when a plurality of candidate PSS / SSS sequences are prepared and the terminal apparatus has a plurality of candidate ULB-CCs that transmit ACK / NACK for uplink data or downlink data, the PSS / SSS Depending on the sequence, it may be notified which CC (ULB-CC or CC) transmits these signals. In the present embodiment, in the case where the PSS / SSS is a sequence used when the amount of data buffered for downlink in the ULB base station apparatus exceeds the threshold, the terminal apparatus performs carrier sense. However, the ULB base station apparatus May have a career sense. In such a case, when the ULB base station apparatus determines that the uplink subframe is a valid subframe as a result of carrier sense, the ULB base station apparatus notifies the terminal apparatus by transmitting PSS / SSS. The transmission timing of the PSS / SSS may be any timing of the special subframe, for example, may be transmitted using a part of OFDM symbols (such as the last OFDM symbol) of DwPTS, or may be transmitted using a part of GP. However, it may be transmitted using some OFDM symbols of UpPTS. The present embodiment can also be applied to FDD. When there are downlink and uplink CCs in the ULB-CC, the effective subframe or the invalid subframe is determined depending on the PSS / SSS sequence transmitted by the ULB base station apparatus. What is necessary is just to notify whether the terminal device needs to perform carrier sense in the subframe before transmission of ACK / NACK by UL information on the frame and uplink ULB-CC. Although the present embodiment has been described by focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, the ACK / NACK transmission timing of this embodiment may be applied to each ULB-CC. The timing of the ULB-CC subframe of this embodiment may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus.

  As described above, in the present embodiment, it is necessary for the terminal apparatus to perform carrier sense before the uplink subframe and the information on the valid subframe or the invalid subframe based on the PSS / SSS sequence transmitted by the ULB base station apparatus. Notify As a result, even if another system occupies the ULB-CC during the uplink data transmission from the timing at which the ULB base station apparatus senses the carrier, collision can be avoided, and the communication quality in the ULB-CC deteriorates. By suppressing the frequency utilization efficiency is improved.

(Modification 1 of 4th Embodiment)
In this modification, the ULB base station apparatus determines whether it is a valid subframe or an invalid subframe in the carrier sense subframe as in the previous embodiment, and if it is a valid subframe, the ULB base station apparatus transmits PSS / SSS. A method for transmitting uplink data in the case of doing so will be described.

  In this modification, the configuration examples of the ULB base station device and the terminal device are the same as those in the first embodiment, and are shown in FIGS. 4 and 6, respectively. The configuration example of the DL signal generation unit 101 of the ULB base station apparatus is the same as that of the first embodiment, and is as shown in FIG. Therefore, in this modification, only different processing will be described, and description of similar processing will be omitted.

  This modification will be described with reference to FIG. In this modification, the S / P unit 1011 of the ULB base station apparatus is different from the first embodiment. When the CS determination unit 106 determines that the subframe # 0 of the frame # 0 is an effective subframe that is not occupied by another system, information on the effective subframe is input to the S / P unit 1011. The data amount management unit included in the S / P unit 1011 manages information on the amount of data buffered for transmission, and when the data amount falls below the threshold, dummy data is transferred to the data signal generation unit 1012-1, Input to 1012-2. Here, the threshold of the buffered data amount for determining whether or not dummy data is input may be determined in advance by the system.

  If there is no downlink data, it may be determined that another system performs carrier sense in subframes # 6 and 7 of frame # 0, and ULB-CC is not used. May start communication. Therefore, the ULB base station apparatus transmits dummy data so that it can be recognized that communication is being performed between the ULB base station apparatus and the terminal apparatus even if another system performs carrier sense. Note that the density of the reference signal may be increased instead of the dummy data.

  In the present modification, the example of uplink data transmission in FIG. 12 has been described, but the present invention can also be applied until the transmission timing of ACK / NACK for downlink data in FIG. Further, instead of transmitting dummy data, the ULB base station apparatus may transmit RTS or CTS-to-self, or may set NAV.

  Although the present embodiment has been described by focusing on one of the ULB-CCs, a plurality of ULB-CCs may exist. In that case, the ACK / NACK transmission timing of this embodiment may be applied to each ULB-CC. The timing of the ULB-CC subframe of this embodiment may be synchronized by synchronizing between the ULB base station apparatus and the terminal apparatus, or the timing of the LB-CC and subframe of the macro base station apparatus. Thus, the timing may be matched between the ULB base station apparatus and the terminal apparatus.

  As described above, in the present modification, the ULB base station apparatus can secure resources from uplink resource allocation to uplink transmission. As a result, it is possible to avoid collision by eliminating another system from occupying the ULB-CC during the uplink data transmission from the timing when the ULB base station apparatus senses the carrier, and the communication quality in the ULB-CC is degraded. By suppressing the frequency utilization efficiency is improved.

  The program that operates in the base station apparatus and the terminal apparatus related to the present invention is a program (a program that causes a computer to function) that controls the CPU and the like so as to realize the functions of the above-described embodiments related to the present invention. Information handled by these devices is temporarily stored in the RAM at the time of processing, then stored in various ROMs and HDDs, read out by the CPU, and corrected and written as necessary. As a recording medium for storing the program, a semiconductor medium (for example, ROM, nonvolatile memory card, etc.), an optical recording medium (for example, DVD, MO, MD, CD, BD, etc.), a magnetic recording medium (for example, magnetic tape, Any of a flexible disk etc. may be sufficient. In addition, by executing the loaded program, not only the functions of the above-described embodiment are realized, but also based on the instructions of the program, the processing is performed in cooperation with the operating system or other application programs. The functions of the invention may be realized.

  In addition, when distributing to the market, the program can be stored and distributed in a portable recording medium, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer is also included in the present invention. Further, part or all of the base station apparatus and terminal apparatus in the above-described embodiment may be realized as an LSI that is typically an integrated circuit. Each functional block of the base station apparatus and the terminal apparatus may be individually chipped, or a part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. When each functional block is integrated, an integrated circuit controller for controlling them is added.

  Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  The present invention is not limited to the above-described embodiment. The terminal device of the present invention is not limited to application to a mobile station device, but is a stationary or non-movable electronic device installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment Needless to say, it can be applied to air conditioning equipment, office equipment, vending machines, and other daily life equipment.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention. The present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention. It is. Moreover, it is the element described in each said embodiment, and the structure which substituted the element which has the same effect is also contained.

  This international application claims priority based on Japanese Patent Application No. 2014-137378 filed on July 3, 2014, and the entire contents of Japanese Patent Application No. 2014-137378 are hereby incorporated by reference. Included in international applications.

DESCRIPTION OF SYMBOLS 10 ... Macro base station apparatus 11 ... ULB base station apparatus 21, 22 ... Terminal device 101 ... DL signal generation part 102-1 to 102-2 ... Radio transmission part 103-1 to 103-2 ... Transmission antenna 104 ... Reception antenna 105 ... Wireless receiver 106 ... CS determining part 107 ... UL signal demodulating part 1011 ... S / P part 1012-1 to 1012-2 ... Data signal generating part 1013-1 to 1013-2 ... Synchronization signal multiplexing part 1014-1 to 1014 -2 ... Control signal multiplexing unit 1015-1 to 1015-2 ... Reference signal multiplexing unit 1016-1 to 1016-2 ... Synchronization signal generation unit 1017-1 to 1017-2 ... Control signal generation unit 1018-1 to 1018-1 Reference signal generators 1019-1 to 1019-2 IFFT units 201-1 to 201-2 Receiving antennas 202-1 to 202-2 Wireless reception Units 203-1 to 203-2 ... FFT units 205-1 to 205-2 ... control signal separation units 206-1 to 206-2 ... reference signal separation unit 207 ... received signal detection unit 208 ... propagation path estimation unit 209 ... control Signal detection unit 210 ... Effective subframe determination unit 211 ... UL signal generation unit 212 ... UL control information multiplexing unit 213 ... Radio transmission unit 214 ... Transmission antenna 215 ... UL control information generation unit

Claims (11)

A base station device that communicates with a terminal device in a second frequency band different from the first frequency band that can be used exclusively,
A wireless transmission unit for transmitting data and control information to the terminal device;
A wireless reception unit for receiving data and control information transmitted from the terminal device,
When the wireless transmission unit transmits data to the terminal device and another system performs communication in the second frequency band at the reception timing of ACK / NACK for the data transmission, the wireless reception unit A base station apparatus that performs reception processing of ACK / NACK transmitted from the terminal apparatus in the first uplink subframe after the communication of the system in FIG.   The wireless transmission unit transmits resource allocation control information for data transmission of the terminal device, and when another system performs communication in the second frequency band at a data reception timing for the resource allocation, The base station apparatus according to claim 1, wherein the radio reception unit performs a reception process of data transmitted from the terminal apparatus in a first uplink subframe after communication of the other system is completed. A base station device that communicates with a terminal device in a second frequency band different from the first frequency band that can be used exclusively and the first frequency band,
A wireless transmission unit for transmitting data and control information to the terminal device;
A wireless reception unit for receiving data and control information transmitted from the terminal device,
When the wireless transmission unit transmits data to the terminal device and another system performs communication in the second frequency band at the reception timing of ACK / NACK for the data transmission, the wireless reception unit A base station apparatus that performs reception processing of ACK / NACK transmitted from the terminal apparatus in one frequency band.   The wireless reception unit receives data transmitted from the terminal device, and when another system performs communication in the second frequency band at an ACK / NACK transmission timing for the data transmission, The base station apparatus of Claim 3 which transmits ACK / NACK to the said terminal device in the frequency band of this. A data amount management unit for managing the amount of downlink buffered data;
The base station apparatus according to claim 3, wherein, when there is no downlink buffered data amount, the radio transmission unit notifies NAV by RTS or CTS-to-Self, or transmits dummy data. A terminal device that communicates with a base station device in a second frequency band different from the first frequency band that can be used exclusively,
An effective subframe determination unit for detecting a synchronization signal transmitted from the base station device;
A received signal detector for receiving data signals transmitted from the base station device;
A wireless transmission unit for transmitting a signal to the base station device,
When the radio transmission unit transmits an ACK / NACK indicating whether the data signal transmitted from the base station apparatus has been correctly received by the reception signal detection unit, 4 subframes after the timing of receiving the data signal Terminal device that transmits the ACK / NACK after receiving a notification that an effective subframe determination unit has received a notification that no other system than the base station device is communicating in the second frequency band. . A control signal detector for detecting control information including resource allocation used for data transmission to the base station device;
When the control signal detection unit detects control information including resource allocation used for data transmission transmitted from the base station device,
The radio transmission unit notifies an uplink subframe four subframes after the timing of receiving the resource allocation, and that a system other than the base station apparatus is not communicating in the second frequency band. The terminal apparatus according to claim 6, wherein the terminal apparatus transmits data to the base station apparatus after reception. A wireless receiver that performs carrier sense to determine whether another system is communicating in the second frequency band;
The terminal apparatus according to claim 6, wherein the radio reception unit performs carrier sense in a subframe that switches from a downlink to an uplink.   The subframe in which the radio reception unit switches from the downlink to which the carrier sense is performed to the uplink is the uplink from the downlink before the subframe in which the ACK / NACK for the data transmitted to the base station apparatus or the ACK / NACK is transmitted. The terminal device according to claim 8, wherein the terminal device is a subframe that is switched to.   The terminal apparatus according to claim 8, wherein the radio reception unit performs carrier sense only in a frequency band for transmitting the ACK / NACK for data to be transmitted to the base station apparatus or downlink data. The effective subframe determining unit cannot detect the synchronization signal transmitted from the base station apparatus, or another system is communicating in the second frequency band as a result of carrier sense of the radio receiving unit. If
The terminal apparatus according to claim 8, wherein the radio reception unit uses a first frequency band for transmission of the ACK / NACK for data to be transmitted to the base station apparatus or downlink data.

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